JP2560831Y2 - Image forming device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine which switches between an exposure mode in which a document is fixed and an exposure mode in which a document is moved by a folding mirror.

[0002]

2. Description of the Related Art Conventionally, in an apparatus having two or more exposure modes, that is, an exposure mode in which a document is fixed and an exposure mode in which a document is moved, the switching is performed by a movable tiltable mirror.

[0003]

However, when a copier having two exposure modes, that is, an exposure mode for fixing the original and an exposure mode for moving the original, is used to switch the exposure mode using a collapsible mirror. When the retractable mirror is in the retracted state, there is a case where the retractable mirror is stopped and left for a long period of time. At that time, dust, dust, and the like in the machine adhere to the retractable mirror.
Therefore, when a mirror to which dirt, dust, and the like are attached is used, it is impossible to exhibit sufficient light reflection performance, resulting in a disadvantage that an image is deteriorated.

[0004]

In order to solve the above-mentioned problems, the present invention provides an optical system movement mode in which an exposure unit is moved to a document stationary on a document glass to perform exposure. An image forming apparatus having a document moving mode in which a document is fixed and moved to perform exposure by moving the document, wherein the switching between the optical system moving mode and the document moving mode is performed by a movable tiltable mirror; When not in use, a dustproof shutter for covering the folding mirror is provided.

[0005]

1 and 2 are sectional views of a copying apparatus to which the present invention can be applied. In the figure, A is a document moving exposure unit, B is a copying machine main body, and C is an automatic document feeder.

First, the optical system movement mode will be described with reference to FIG. For normal copying, an original is set on the tray 14 of the automatic document feeder C, the document is automatically transported, and the document is automatically transported, and the original document is placed on the original glass 1 in the RF mode. In the book mode (pressing plate mode) in which the original is fixed with the hand. that time,
The exposing device of the copying machine main body including the exposure lamp 2, the reflection shade 4, and the first mirror 3 scans the original as indicated by an arrow, and returns to the position shown in the figure when the exposure of the original is completed (home position). At this time, the second mirror 5 and the third mirror 6, which receive the reflection shade from the first mirror and are fixed in a hano shape by the same frame, move in synchronization with the movement of the first mirror and move the first mirror. It is configured to move at half the speed and keep the optical path length constant.

Further, the light reflected by the third mirror passes through the zoom lens 7 and is reflected by the fourth mirror box 8 to form an image on the photosensitive member 9.

This is the optical system moving mode (document fixed exposure mode).

Next, the document moving exposure mode will be described with reference to FIG.

The automatic document feeder C is opened, and a document moving exposure unit which is rotated by a link mechanism is set in the copying machine main body B. At this time, positioning with respect to the main body is performed by fitting a pin coming out of the original moving exposure unit with a hole of the main body. Then, the first mirror base D moves to the left from the first mirror home position in order to secure an optical path in the case of document movement.
Then, the light coming from the exposure device in the original moving exposure unit passes through the zoom lens 7 and forms an image on the photosensitive member 9. Stands up at an angle of about 45 ° as shown in FIG. 4 to secure an optical path from the original moving exposure unit.

At this time, the position of the mirror is determined by contacting the contact portion from the main body.

Next, a description will be given of lifting and lowering of the foldable mirror and opening and closing of a dustproof shutter of the foldable mirror according to an embodiment of the present invention.

FIGS. 3 and 4 are enlarged views of the periphery of the tiltable mirror.

FIG. 3 shows a state in which the folding mirror unit is normally retracted, that is, a state in which a copy is taken in the original fixing mode. Foldable mirror 13 is mirror frame 1
9 hold both ends thereof, and are configured to be able to move within the mirror frame by being pressed against the contact portion 19a of the mirror frame 19 by the leaf spring 24.

The mirror frame 19 is held by a frame 21 so as to be rotatable about a rotation shaft 20. Further, a retractable mirror dustproof shutter 23 disposed on the frame 21 so as to cover the retractable mirror 13 is also held rotatably about a rotation shaft 26. The dustproof shutter is a rotating shaft 2
The torsion mirror is pushed down by a torsion coil spring 28 attached to 6.

As described above, in this embodiment, since the dustproof shutter is provided on the retractable mirror, dust and dirt do not adhere to or accumulate without using the retractable mirror for a long time. It is possible to prevent deterioration of optical accuracy when using the mirror. In addition, since the dustproof shutter can prevent the tiltable mirror from rising, there is an effect of preventing interference with the mirror base, vibration of the tiltable mirror, and the like. This has the effect of preventing vibration of the mirror and the like.

When copying is performed in the exposure mode for moving the original, the tilting mirror is raised by rotating the elevating arm 22 as shown in FIG. At this time, the rotation force of the lifting arm is given by the motor M via the gear 27 attached to the rotation shaft 30.

The mirror frame 19 is pushed up by the rotation of the elevating arm, and the mirror frame pushes up the collapsible mirror dustproof shutter 23 and rotates about the rotation shaft 26 in conjunction with this movement, whereby the collapsible mirror is rotated. Is 45
° when standing up, the retractable mirror dustproof shutter escapes,
An optical path from the document moving exposure unit is secured. The position of the up / down movement of the folding mirror at that time is detected by the photo interrupter 25.

The adjustment of the optical path between the original moving exposure unit and the main body is performed by a set screw 29 previously adjusted on the main body side.
The optical path is determined by arranging a mirror on the mirror. The set screws 29 are located at both ends in the longitudinal direction of the retractable mirror 13 and do not interfere with the first, second, and third mirrors 3, 5, and 6.

As described above, in this embodiment, since the dustproof shutter opens and closes in conjunction with the movement of the tiltable mirror, there is no need to provide a drive motor for the dustproof shutter, and the device configuration is simplified.

[0021]

[Effect of the Invention] As described above, the present invention provides a dust-proof shutter on the collapsible mirror so that copying is mainly performed in the original fixed mode, and the collapsible mirror can be left in a retracted state for a long time. It is possible to prevent dust and the like scattered inside from adhering to the tiltable mirror, and to prevent image deterioration by sufficiently reflecting light when the tiltable mirror is used.

[Brief description of the drawings]

FIG. 1 is a sectional view of a copying apparatus when an optical system is moved.

FIG. 2 is a sectional view of the copying apparatus when the optical system is fixed.

FIG. 3 is a diagram illustrating a state in which a tiltable mirror is not used.

FIG. 4 is a diagram showing a state in which a tiltable mirror is used.

[Explanation of symbols]

 A Document Moving Exposure Unit B Copier Body C Document Automatic Transport Device 13 Folding Mirror 23 Dustproof Shutter

Claims (2)

(57) [Scope of request for utility model registration] 1. An optical system movement mode in which an exposure unit is moved to expose a document stationary on a document glass to perform exposure, and a document movement mode in which an exposure unit is fixed at a predetermined position and the document is moved to perform exposure. An image forming apparatus comprising: a movable mirror that switches between the optical system movement mode and the document movement mode using a movable tiltable mirror; and a dustproof shutter that covers the tiltable mirror when the tiltable mirror is not used. An image forming apparatus, comprising: 2. The image forming apparatus according to claim 1, wherein the dustproof shutter moves in conjunction with the tiltable mirror.